"If so, your family tree - and that of every other terrestrial life form - has its deepest roots not in the ancient oceans of Earth, but in the vanished seas of Mars."

Human behaviour: Marvin the Martian was one of many fictional representations of the Red Planet's imaginary populace

This astonishing claim draws on a theory called panspermia, which suggests hardy microorganisms may be able to survive the ravages of space and travel from planet to planet.

These brave beasties' chances of survival may be boosted if they find themselves in a clod of dirt thrown into space when an asteroid collided into the Martian surface.

Although the "the conditions on board are worse than RyanAir", this could allow tiny specks of life to travel to the earth - assuming Mars was ever home to ancient organisms.

"Scientists estimate that in the early days of the solar system, billions of rocks between an inch and a yard in size were involuntarily shuttled from the Red Planet to ours," Shostak continued.

Inhospitable: Could the barren surface of Mars once been home to living organisms? (Image: Reuters)

"In its youth, Mars was wetter and warmer than now, and could have spawned living things at a time when Earth was as lifeless as an octogenarian slumber party.

"Because so many martian rocks were kicked into space, it's highly probable that at least some would have come from an inhabited patch of Mars - assuming it hadinhabitants.

"And some of those would have landed in a suitably welcoming patch of Earth."

With this theory in mind, he called upon NASA and other space exploring agencies to extend their search for alien life to the other planets of the solar system, claiming life could "be as common as fast food".